Summit engine blocks
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
Summit engine blocks Anyone use these? Thinking about doing a budget build to handle 15 psi.
https://www.summitracing.com/parts/sum-150157
https://www.summitracing.com/parts/sum-150157
Budget build? You can find a nice, running junkyard engine for much less, that will be complete. Starting with just a block can be very pricey. I know this all too well, as I just went through the process.
Summit purchased most all (from what I read) of GM’s remaining LS overstock blocks, when GM officially shut down the LS line, and re-tooled for the LT line. It’s not a Summit block. It’s a GM block sold by Summit.
Summit purchased most all (from what I read) of GM’s remaining LS overstock blocks, when GM officially shut down the LS line, and re-tooled for the LT line. It’s not a Summit block. It’s a GM block sold by Summit.
Budget build? You can find a nice, running junkyard engine for much less, that will be complete. Starting with just a block can be very pricey. I know this all too well, as I just went through the process.
Summit purchased most all (from what I read) of GM’s remaining LS overstock blocks, when GM officially shut down the LS line, and re-tooled for the LT line. It’s not a Summit block. It’s a GM block sold by Summit.
Summit purchased most all (from what I read) of GM’s remaining LS overstock blocks, when GM officially shut down the LS line, and re-tooled for the LT line. It’s not a Summit block. It’s a GM block sold by Summit.
Plus it's nice having a seasoned block as well.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
I get that it's a GM block. When I said Summit engine block I meant a block prepared by Summit, their machine work. Budget to me is a short block under $4000 built by me with forged pistons to handle 15 psi reliably. I know junk yard motors have handled much more, but it's hit or miss and may not be reliable. I also understand there are short blocks by both Thompson, Texas speed, and others that fit the bill under $4000. Just considering doing a cheap motor myself to learn. I can do a lot of things and tune myself, but never built a short block before. It just interests me and I don't want my first one to be a high dollar build.
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
It would be MORE educational to get a worn LS and tear it down to see how it's built first, THEN going thru and reconditioning/replacing those parts needing it after you've checked them over. THEN you get to assemble them into an engine you KNOW has good parts in it,
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
I do my own work and tuning so I'm not oblivious to how engines are built. I've just not built my own short block so it's something I want to do. I don't even need a motor right now, but I'd rather have something ready to go before I do need it.
Last edited by BCNUL8R; Aug 25, 2018 at 06:32 AM.
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Cool. For me, the best thing about buying a running engine, is that it’s all there and you know it’s decent. Yeah, the crank might need turned, and the rods touched up, but it’s straight. If you buy a crank used off of somebody, who knows how many times it fell over in their garage? Maybe they didn’t pack it properly, and then UPS guy is having a bad day, so he’s throwing the heavy thing around all day in his truck...you know what I mean? On the other hand, if you purchase the block from Summit, or even a used block off of craigslist for a hundred bucks, you can fill it with new parts that a vendor will stand behind.
Do your homework. You can buy an assembly cheaper than buying parts separate. For performance and reliability you’ll want to bore the block to your pistons size, not buy the pistons for the bore size you have. Enjoy the journey. Ask questions along the way. Have fun with the hobby, because that’s what it’s supposed to be...fun!
Do your homework. You can buy an assembly cheaper than buying parts separate. For performance and reliability you’ll want to bore the block to your pistons size, not buy the pistons for the bore size you have. Enjoy the journey. Ask questions along the way. Have fun with the hobby, because that’s what it’s supposed to be...fun!
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Verdad Gallardo Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
Cool. For me, the best thing about buying a running engine, is that it’s all there and you know it’s decent. Yeah, the crank might need turned, and the rods touched up, but it’s straight. If you buy a crank used off of somebody, who knows how many times it fell over in their garage? Maybe they didn’t pack it properly, and then UPS guy is having a bad day, so he’s throwing the heavy thing around all day in his truck...you know what I mean? On the other hand, if you purchase the block from Summit, or even a used block off of craigslist for a hundred bucks, you can fill it with new parts that a vendor will stand behind.
Do your homework. You can buy an assembly cheaper than buying parts separate. For performance and reliability you’ll want to bore the block to your pistons size, not buy the pistons for the bore size you have. Enjoy the journey. Ask questions along the way. Have fun with the hobby, because that’s what it’s supposed to be...fun!
Do your homework. You can buy an assembly cheaper than buying parts separate. For performance and reliability you’ll want to bore the block to your pistons size, not buy the pistons for the bore size you have. Enjoy the journey. Ask questions along the way. Have fun with the hobby, because that’s what it’s supposed to be...fun!
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Joined: Nov 2016
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From: PNW
Something else you should take into consideration - GM is a massive company that spent millions developing and building these engines with specialized equipment and machinery - do you honestly think you can even remotely do the same job yourself? Serious question - not being a dick - just something to consider before you dismiss a used, proven stock engine over building your own.
Something else you should take into consideration - GM is a massive company that spent millions developing and building these engines with specialized equipment and machinery - do you honestly think you can even remotely do the same job yourself? Serious question - not being a dick - just something to consider before you dismiss a used, proven stock engine over building your own.
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Joined: Nov 2016
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From: PNW
The type of rings you use, the clearances you give, the grinds, the cuts - SO many factors come into play here, the list just goes on and on - and every little thing makes a big difference to the finished product as each thing just compounds one another. If your main goal is to build a motor, then yeah, have at it - but if you’re more concerned with just having a good running car to go have fun with - save the engine building for GM.
The type of rings you use, the clearances you give, the grinds, the cuts - SO many factors come into play here, the list just goes on and on - and every little thing makes a big difference to the finished product as each thing just compounds one another. If your main goal is to build a motor, then yeah, have at it - but if you’re more concerned with just having a good running car to go have fun with - save the engine building for GM.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
The type of rings you use, the clearances you give, the grinds, the cuts - SO many factors come into play here, the list just goes on and on - and every little thing makes a big difference to the finished product as each thing just compounds one another. If your main goal is to build a motor, then yeah, have at it - but if you’re more concerned with just having a good running car to go have fun with - save the engine building for GM.
My current ls1 only has 30,7xx miles on it and is running fine. I'm running 10 psi right now, but plan to keep slowly adding boost over time. I don't expect to build a 100,000 mile engine. What I want is a motor that will handle 700+ rwhp using a procharger and auto trans reliably. For every junk yard motor making 1000+ rwhp posted all over the internet there are several more stories of them blowing up that are never told.
It's a GM block so that's established and cool.
It's summit, they shouldn't have issues with machining, they aren't a two bit corner store if you smell what I'm cooking.
If you're real concerned drop it off at the machine shop to be inspected.
I say buy the block and build your motor man.
Sorry, I have no experience with that specific block to answer your original question.
It's summit, they shouldn't have issues with machining, they aren't a two bit corner store if you smell what I'm cooking.
If you're real concerned drop it off at the machine shop to be inspected.
I say buy the block and build your motor man.
Sorry, I have no experience with that specific block to answer your original question.
I'd just get the regular LM7 they sell for $349 shipped. You want your pistons to match the machining - that already machined block would be fine for a factory rebuild with stock pistons. But not for a boosted setup... plus not a huge selection in 3.898 aftermarket for boost. So buy the block or get a JY block and grab your pistons and take to a local machine shop. There's bound to be a good one within 50 miles.
Also, for others who have said it. You can't buy a built shortblock for less than you can build your own. Most machine shops will hone/bore with a torque plate the pistons and balance the rotating assembly for about $500. Cleaning of the block $50. Add a line bore if you do ARP studs. Another 200 or so for that. If the block needs more work that that, it's not worth it. Get another one.
And most good rotating assemblies are in the $2000-2200 range with K1/Molnar/Compstar Rods/Crank and Wiseco pistons with upgraded pins. Plus whatever the block costs. Then the bearings and ARP studs. Another $350 for that.
What does that come out to? About $3600. See who will build you an all forged shortblock with ARP mains, upgraded H-13 pins, and a 5.3 or 6L block for $3600? Nobody. Tack on another $1k to that AT LEAST. Plus shipping.
Also, for others who have said it. You can't buy a built shortblock for less than you can build your own. Most machine shops will hone/bore with a torque plate the pistons and balance the rotating assembly for about $500. Cleaning of the block $50. Add a line bore if you do ARP studs. Another 200 or so for that. If the block needs more work that that, it's not worth it. Get another one.
And most good rotating assemblies are in the $2000-2200 range with K1/Molnar/Compstar Rods/Crank and Wiseco pistons with upgraded pins. Plus whatever the block costs. Then the bearings and ARP studs. Another $350 for that.
What does that come out to? About $3600. See who will build you an all forged shortblock with ARP mains, upgraded H-13 pins, and a 5.3 or 6L block for $3600? Nobody. Tack on another $1k to that AT LEAST. Plus shipping.
Something else you should take into consideration - GM is a massive company that spent millions developing and building these engines with specialized equipment and machinery - do you honestly think you can even remotely do the same job yourself? Serious question - not being a dick - just something to consider before you dismiss a used, proven stock engine over building your own.
Thread Starter
Joined: Jun 2005
Posts: 2,265
Likes: 671
From: Oskaloosa, Iowa
Agreed. Most people would be absolutely dumbfounded if they had a clue as to the resources and engineering that went into developing this engine platform. The failure modes of these engines are well documented so we can predict reliability in many scenarios. Simply using an inexpensive stock engine for a street build is great advice.
TECH Resident
Joined: Jul 2007
Posts: 967
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From: Winter Haven FL
Best bet is to find out the common consensus in the forced induction section. If you're going with a new engine for the next build there's no reason it has to be gen 3 based. Finding parts for a LS3 Camaro makes things go much faster. If you're set on a brand new block you could even go LSA/LSX if you want to.
At this point I'm not going to try to talk you out of building your first engine. It could be easily argued that it would be rather hypocritical of me to do so. My only intent is to make you aware of the rabbit hole you're about to go down so you can make a good decision as to whether or not your time and money are worth the experience.
Your statement above leads me to believe that you don't have any of the tools required for measuring clearances in the engine. So I have to ask the question. Are you aware of the tools and processes required? This is a question you have to answer to yourself, not me. I don't need a reply.
I do have to reiterate, learning to build an engine the right way, the first time, will cost more than simply buying one. Unfortunately, "budget build" "first engine build" and "700 at the wheels through an automatic" can't realistically be used in the same conversation.
Your statement above leads me to believe that you don't have any of the tools required for measuring clearances in the engine. So I have to ask the question. Are you aware of the tools and processes required? This is a question you have to answer to yourself, not me. I don't need a reply.
I do have to reiterate, learning to build an engine the right way, the first time, will cost more than simply buying one. Unfortunately, "budget build" "first engine build" and "700 at the wheels through an automatic" can't realistically be used in the same conversation.